On his current expedition, Ronald Clouse ventures into the jungles of the Philippines to study harvestmen, or daddy-long-legs, of the order Opiliones. By collecting data for phylogenetic analysis, he hopes to learn more about the history of these creatures and the lands they inhabit.The sun sets over a beach in Pandan, Panay Island. (Photo by Ron Clouse)
Tuesday night, May 14th, I arrived in Manila via Hawaii and Guam. Guam always looks small when coming from Hawaii, huge when coming from a long stay in the aptly named islands of Micronesia. I was met at the airport by project member Dr. Prashant Sharma, who has been here collecting on the island of Luzon since late April. He collected daddy-long-legs—I’ll call them by their arachnid order name of Opiliones, pronounced “OH-pill-ee-OH-nez,” from here on—in several locations previously unsurveyed for these interesting animals: Mt. Palay-Palay, southwest of Manila; Mt. Banahaw, southeast of Manila; Adams, in northern Luzon; and the beach resort of Pagudpud, also in the North.
That night we were joined by project member and PhD student Dave General, who will be joining us in the field later, and the next morning we went to the National Museum of the Philippines to meet with project members and museum researchers Perry Buenavente (who has made all the arrangements for this expedition!) and John Rey Callado. After final paperwork was completed, Prashant, Perry, John Rey, and I headed to the airport to fly to Panay Island, where we are now, preparing to collect in the forest near Pandan, far in the Northwest of the island. In a few hours we will leave for Sibaliw Research Station. To get there, we’ll climb about four hours from the coast into the forest at about 500-meters elevation. There we will be sifting leaf litter and collecting Opiliones for several days.
We are being helped with our arrangements in Panay by the Panay Eco-Social Conservation Project (PanayCon), formerly known as the Philippine Endemic Species Conservation Project. We visited their offices in the afternoon, and in the course of talking saw the homemade guns confiscated by the organization. Made from PVC pipe, plastic bottles, wood, and other materials, they are used to hunt various forest animals, including protected birds.
We are excited to be in Panay, especially this region, as it appears to have the chance of being continental in origin. Certain plant and animal taxonomic groups here (including certain Opiliones) resemble elements found on Palawan Island to the west, which is hypothesized to be a piece of the Chinese coastline that moved east to its present location as the South China Sea opened up 20–30-million years ago.
The Philippines may appear to be a cohesive archipelago with a single origin, but the islands arrive from different locations, formed by different processes, and in some cases single islands are composites of different terranes from different beginnings. Geologists hypothesize the origins of the islands based on various pieces of physical evidence gathered from the rocks and deposits here. Opiliones provide an excellent opportunity to test those hypotheses, as they have very poor dispersal abilities and are often distributed in regions due to the movements of the landmass on which they live.
The Opiliones least likely to disperse are in the group (brace yourself!) “Cyphophthalmi.” These small, thick-legged animals look like seeds in the leaf litter, and they are known from only three juveniles and one adult in the Philippines. Not coincidentally, they are known from islands that have had hypothetical continental origins, at least in part: Palawan and Mindanao. Continental landmasses have been above water for far longer than land originating as volcanoes from the sea floor, and they can drift around, connect and split from other landmasses, and carry animals reluctant or unable to cross open ocean. We will collect on Minadanao next month, but for now we are excited to see if there is evidence here on Panay of it once being connected to Palawan.